Cross-correlating cosmic microwave background radiation fluctuations with redshift surveys: Detecting the signature of gravitational lensing

Maki Suginohara, Tatsushi Suginohara, David N. Spergel

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Density inhomogeneities along the line of sight distort fluctuations in the cosmic microwave background. Usually, this effect is thought of as a small second-order effect that mildly alters the statistics of the microwave background fluctuations. We show that there is a first-order effect that is potentially observable if we combine microwave background maps with large redshift surveys. We introduce a new quantity that measures this lensing effect, 〈T(δθ ·VT)〉 , where T is the microwave background temperature and δθ is the lensing due to matter in the region probed by the redshift survey. We show that the expected signal is first order in the gravitational lensing bending angle, 〈(δθ)2〉1/2, and find that it should be easily detectable, signal-to-noise ratio ∼ 15-35, if we combine the Microwave Anisotropy Probe satellite and Sloan Digital Sky Survey data. Measurements of this cross-correlation will directly probe the "bias" factor, i.e., the relationship between fluctuations in mass and fluctuations in galaxy counts.

Original languageEnglish (US)
Pages (from-to)511-515
Number of pages5
JournalAstrophysical Journal
Volume495
Issue number2 PART I
DOIs
StatePublished - Jan 1 1998

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Cosmic microwave background
  • Galaxies: distances and redshifts
  • Gravitational lensing
  • Large-scale structure of universe
  • Methods: statistical

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